The present invention relates generally to an improved fluid flow system for providing a medium for exchange or for the extracting of thermal energy in skating rinks. The system of the present invention is an improvement over that system disclosed and claimed in U.S. Pat. No. 3,466,892, dated Sept. 16, 1969 and U.S. Pat. No. 3,831,394, dated Aug. 27, 1974.
A fundamental feature of the system is to provide a means for the uniform circulation of liquid refrigerant to the large area being refrigerated, wherein substantially uniform pressures and corresponding equalization of pressure differentials are achieved across the distribution system and in the areas being treated. Uniformity in ice in the rink is achieved in this fashion. In the refrigeration system utilized in the combination of the present invention, the refrigeration system utilizes a compressor means for compressing a refrigerant, means for delivering the compressed refrigerant to a low pressure receiver vessel, and means for passing refrigerant condensate from a low pressure vessel to a pair of pumper drum vessels. Refrigerant is delivered from the pumper drum vessels to the ice rink per se through the distribution system of U.S. Pat. No. 3,831,394, with the present improvement providing a means for controllably providing chilled refrigerant from the pumper drums to the ice rink.
In the low pressure receiver, a portion of the liquid refrigerant undergoes a phase transformation to deliver a refrigerating effect to the refrigeration area by means of the propulsion achieved by fluids in the liquid state under high pressure and substantially directly from the compressor device. This technique eliminates the necessity of transmission or circulation of liquid refrigerant at extremely low temperatures, and permits operation at a reasonably constant temperature which is in the range of between about 15.degree.-18.degree. F. This temperature is one which results in an ice surface which is deemed ideal for ice hockey or figure skating, and this system accomplishes the result with unusually high efficiency. Since refrigerant delivered from the compressor is in the form of high pressure-high temperature gas, and is condensed in the conventional condenser column, whereupon the gaseous refrigerant is converted to high pressure-high temperature liquid. In order to more carefully control the temperature of the chilled refrigerant in the pumper drums, an expansion orifice is employed adjacent the upper portion of the pumper drum so as to accomplish a liquid-to-gas phase conversion and resultant cooling.
In order to equalize the flow of chilled low pressure-low temperature refrigerant through the system, and in order to eliminate wide pressure differentials, a balance header is provided which extends between opposed ends of the high pressure header at one end of the rink. An intermediate line is also provided which couples the central or mid-portions of the high pressure header and the balance header together. In this fashion, uniformity of ice conditions without presence of warm areas of soft or wet ice is provided. The intermittent pressurized system coupled to the pumper drums provides a distribution system for low pressure-low temperature refrigerant which achieves a high degree of uniformity of ice conditions, particularly when coupled with the balance header of U.S. Pat. No. 3,831,394.